Multi charged particle beam exposure method and multi charged particle beam exposure apparatus

Patent metadata

Field	Value
Publication number	US-10134565-B2
Application number	US-201715831729-A
Country	US
Kind code	B2
Filing date	Dec 5, 2017
Priority date	Dec 8, 2016
Publication date	Nov 20, 2018
Grant date	Nov 20, 2018

Abstract

A multi charged particle beam exposure method includes calculating an effective irradiation time, for each of a plurality of control irradiation time periods for controlling an irradiation time of each beam in the multi-beams of a charged particle beam, using a blanking error time of each divided shot of a plurality of divided shots, previously acquired, due to an error of blanking control for each divided shot; generating correlation data representing a relation between the control irradiation time and the effective irradiation time; selecting, using the correlation data, for each irradiation position of a target object, the combination of the divided shots corresponding to the effective irradiation time to be closer to each desired irradiation time; and performing exposure, using the multi-beams, based on the combination of the divided shots selected for each irradiation position of the target object.

First claim

What is claimed is:

1. A multi charged particle beam exposure method comprising:
calculating an effective irradiation time, in a case where an irradiation position of each beam in multi-beams of each pass which indicates each exposure processing in multiple exposure is exposed during a control irradiation time being a desired irradiation time by continuously performing a combination of divided shots selected from a plurality of divided shots each having any one of a plurality of sub control irradiation time periods preset and being corresponding to the control irradiation time onto a same irradiation position, for each of a plurality of control irradiation time periods for controlling an irradiation time of each beam in the multi-beams of a charged particle beam, using a blanking error time of each divided shot of the plurality of divided shots, previously acquired, due to an error of blanking control for the each divided shot;
generating correlation data which represents a relation between the control irradiation time and the effective irradiation time;
selecting, using the correlation data, for each irradiation position of a target object, the combination of the divided shots corresponding to the effective irradiation time to be closer to the each desired irradiation time; and
performing exposure, using the multi-beams, based on the combination of the divided shots selected for the each irradiation position of the target object.

2. The method according to claim 1 , wherein
the combination of the divided shots is selected for the each pass which indicates the each exposure processing in the multiple exposure, and selected so that a total of the effective irradiation time obtained by the combination of the divided shots selected for the each pass becomes closer to a desired irradiation time for all passes in the multiple exposure.

3. The method according to claim 1 , further comprising:
measuring a first pattern dimension of an evaluation pattern formed in a case of performing exposing by at least one beam of the multi-beams without using a divided shot, onto an evaluation substrate during each of a plurality of first control irradiation time periods for evaluation, each of which is different from each other and sufficiently longer than a settling time needed in the blanking control of the each beam;
measuring a second pattern dimension of the evaluation pattern formed in a case of performing combination of exposing by the at least one beam of the multi-beams without using a divided shot during a second control irradiation time for evaluation which is sufficiently longer than the settling time, and exposing by the at least one beam of the multi-beams using a target divided shot in the plurality of divided shots by repeating a plurality of times, onto the evaluation substrate;
approximating a third control irradiation time for evaluation based on which the second pattern dimension is obtained, using a result of the first pattern dimension measured for the each of the plurality of first control irradiation time periods for evaluation; and
calculating the blanking error time with respect to the target divided shot by using the second control irradiation time for evaluation, the third control irradiation time for evaluation, the control irradiation time of the target divided shot, and a number of repeating the target divided shot.

4. The method according to claim 3 , wherein the blanking error time is calculated for a divided shot whose control irradiation time is shorter than the settling time in the plurality of divided shots.

5. The method according to claim 3 , further comprising:
setting a multiplicity (number of passes) used in performing the multiple exposure.

6. The method according to claim 5 , further comprising:
setting, by a gray scale value, a quantization unit for defining an irradiation time in a case of performing the exposing without using a divided shot.

7. The method according to claim 6 , further comprising:
performing the exposing without using a divided shot to a pixel which serves as a unit irradiation region by irradiation of one beam shot without a divided shot during the each of the plurality of first control irradiation time for evaluation, using an evaluation pattern.

8. A multi charged particle beam exposure apparatus comprising:
an effective irradiation time calculation circuit configured to calculate an effective irradiation time, in a case where an irradiation position of each beam in multi-beams of each pass which indicates each exposure processing in multiple exposure is exposed during a control irradiation time being a desired irradiation time by continuously performing a combination of divided shots selected from a plurality of divided shots each having any one of a plurality of sub control irradiation time periods preset and being corresponding to the control irradiation time onto a same irradiation position, for each of a plurality of control irradiation time periods for controlling an irradiation time of each beam in the multi-beams of a charged particle beam, using a blanking error time of each divided shot of the plurality of divided shots, previously acquired, due to an error of blanking control for the each divided shot;
a generation circuit configured to generate correlation data which represents a relation between the control irradiation time and the effective irradiation time;
a selection circuit configured to select, using the correlation data, for each irradiation position of a target object, the combination of the divided shots corresponding to the effective irradiation time to be closer to the each desired irradiation time; and
an exposure mechanism configured to perform exposure, using the multi-beams, based on the combination of the divided shots selected for the each irradiation position of the target object.

9. The apparatus according to claim 8 , wherein
the combination of the divided shots is selected for the each pass which indicates the each exposure processing in the multiple exposure, and
the selection circuit selects the combination of the divided shots for the each pass so that a total of the effective irradiation time obtained by the combination of the divided shots selected for the each pass becomes closer to a desired irradiation time for all passes in the multiple exposure.

10. The apparatus according to claim 8 , further comprising:
a storage device configured to store
a first pattern dimension of an evaluation pattern formed in a case of performing exposing by at least one beam of the multi-beams without using a divided shot, onto an evaluation substrate during each of a plurality of first control irradiation time for evaluation, each of which is different from each other and sufficiently longer than a settling time needed in the blanking control of the each beam, and
a second pattern dimension of the evaluation pattern formed in a case of performing combination of exposing by the at least one beam of the multi-beams without using a divided shot during a second control irradiation time for evaluation which is sufficiently longer than the settling time, and exposing by the at least one beam of the multi-beams using a target divided shot in the plurality of divided shots by repeating a plurality of times, onto the evaluation substrate; and

a control irradiation time calculation circuit for evaluation configured to approximate a third control irradiation time for evaluation based on which the second pattern dimension is obtained, using a result of the first pattern dimension measured for the each of the plurality of first control irradiation time for evaluation.

Assignees

• Nuflare Technology Inc

Inventors

• Matsumoto Hiroshi

Classifications

• G03F7/2059

  using a scanning corpuscular radiation beam, e.g. an electron beam · CPC title

• H01J37/304

  Controlling tubes by information coming from the objects {or from the beam}, e.g. correction signals · CPC title

• H01J37/3177

  Multi-beam, e.g. fly's eye, comb probe · CPC title

• G03F7/70016 Primary

  by discharge lamps · CPC title

• H01J37/3007

  Electron or ion-optical systems · CPC title